Dual-frequency high-isolation compact Beidou third-generation satellite transmitting and receiving integrated antenna

Abstract

The invention discloses a double-frequency high-isolation compact Beidou third-generation satellite receiving and transmitting integrated antenna, relates to the technical field of satellite communication, and solves the technical problem that the isolation degree of two antennas with similar frequency bands in a limited size is relatively poor. The antenna comprises a first antenna, a second antenna and a feed circuit board which are sequentially stacked from top to bottom, the feed circuit board comprises a three-branch strip line coupler, and the three-branch strip line coupler comprises a main coupling line and an auxiliary coupling line which are symmetrically arranged. A first branch line, a second branch line and a third branch line are connected between the main coupling line and the auxiliary coupling line, the left end and the right end of the main coupling line are a first port and a third port respectively, and the left end and the right end of the auxiliary coupling line are a second port and a fourth port respectively; according to the invention, the receiving and transmitting integrated antenna and the feed network are designed in a targeted manner, the BDS L frequency band and the BDS B1 radiation patch can be stacked, and the miniaturization design of the antenna is realized under the condition that the antenna performance is not influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite communication, and particularly relates to a dual-frequency, high-isolation, and compact integrated receiving and transmitting antenna for the third-generation Beidou satellite. Background Art

[0002] The Beidou satellite navigation system has been widely applied in military and civilian fields. As an important front-end device of this system, the performance of the satellite navigation antenna directly affects the performance of the entire system. With the continuous development of satellite navigation technology, the requirements for satellite navigation antennas are getting higher and higher. It not only needs to maintain excellent radiation performance, but also puts forward more requirements for antenna miniaturization, multi-band, multi-polarization, high isolation, etc.

[0003] Currently, satellite communication requires multi-band simultaneous operation. The main required frequency bands of the third-generation Beidou satellite are B3, B1, L, S, and B2b. Among them, L belongs to the transmitting antenna, and the polarization mode is left-hand circular polarization. The antennas of the remaining frequency bands are all receiving antennas, and the polarization mode is right-hand circular polarization. The B1 receiving frequency band of the third-generation Beidou satellite antenna is close to the L transmitting frequency band (L: 1615.68 ± 4.08 MHz, B1: 1575.42 ± 16.368 MHz). The coupling between antennas is serious. When working simultaneously, the B1 receiving frequency band is easily interfered by the L-band transmitting signal. In order not to affect the B1-band receiving performance, the existing method often increases the isolation between antennas by increasing the distance between two antenna elements, but this will increase the volume size of the antenna, which is not conducive to the requirements of miniaturized scenarios. In addition, the existing B1-frequency receiving antenna and L-band transmitting antenna adopt an independent feeding method, which does not meet the characteristics of high integration and miniaturization.

[0004] For the third-generation Beidou receiving and transmitting antenna, the lowest frequency point of L and the highest frequency point of B1 are only separated by dozens of megahertz. When the receiving and transmitting devices work simultaneously, since the intensity of the received signal is often much weaker than that of the transmitted signal, it is easily interfered. In actual products, the installation size of such antennas is usually very limited. The conventional design places two independent antennas flatly at a certain distance, but this method is not feasible. In the existing structure, the antennas can only be stacked, but the isolation between the stacked L antenna and B1 antenna is only about 10 - 20 dB. Summary of the Invention

[0005] Aiming at the technical problem of poor isolation between two antennas with close frequency bands under limited size, the present invention proposes a dual-frequency, high-isolation, and compact integrated receiving and transmitting antenna for the third-generation Beidou satellite, which can solve the problem that the BDS B1 frequency band is easily interfered when the BDS L frequency band and the BDS B1 frequency band work simultaneously, and can be applied to high-integration and miniaturized devices.

[0006] A dual - frequency, high - isolation, compact Beidou - III satellite transceiver integrated antenna, comprising: a first antenna, a second antenna, and a feeding circuit board stacked in sequence from top to bottom. The feeding circuit board includes a three - branch strip - line coupler. The three - branch strip - line coupler includes a main coupling line and a sub - coupling line symmetrically arranged. A first branch line, a second branch line, and a third branch line are connected between the main coupling line and the sub - coupling line. The left and right ends of the main coupling line are a first port and a third port respectively, and the left and right ends of the sub - coupling line are a second port and a fourth port respectively.

[0007] Further, the main coupling line and the sub - coupling line have the same length, the first branch line, the second branch line, and the third branch line have the same length, and the length of the main coupling line is twice the length of the first branch line.

[0008] Further, when any one of the first port, the second port, the third port, and the fourth port is used as an input port, the corresponding port symmetric to it on the other coupling line serves as an isolation port due to the cancellation of electromagnetic waves, and the remaining two ports are output ports.

[0009] Further, the two output ports respectively output signals with equal amplitude and a phase difference of 90°. When transmitted to the first antenna and the second antenna, a left - hand circularly polarized wave or a right - hand circularly polarized wave can be formed.

[0010] Further, the lengths of the main coupling line and the sub - coupling line are 1 / 2 wavelength, the lengths of the first branch line, the second branch line, and the third branch line are 1 / 4 wavelength. The second branch line of the main coupling line and the sub - coupling line is arranged between the first branch line and the third branch line. The main coupling line, the sub - coupling line, and the second branch line have the same impedance. The first branch line and the third branch line have the same impedance, and the impedance of the main coupling line is less than the impedance of the first branch line.

[0011] Further, the feeding circuit board directly feeds the first antenna through a feeding probe, and the second antenna is fed by coupling through a feeding probe.

[0012] Further, the first antenna includes a first dielectric substrate, a first radiation patch arranged on the upper surface of the first dielectric substrate, and a first metal floor arranged on the lower surface of the first dielectric substrate. The second antenna includes a second dielectric substrate, a second radiation patch arranged on the upper surface of the second dielectric substrate, and a second metal floor arranged on the lower surface of the second dielectric substrate.

[0013] Furthermore, the feeding circuit board includes a feeding probe which sequentially passes through the second metal floor, the second dielectric substrate, the second radiation patch, the first metal floor, and the first dielectric substrate and is connected to the first radiation patch. The second radiation patch, the second dielectric substrate, the second metal floor, the first dielectric substrate, and the first metal floor are all not in contact with the feeding probe. The feeding probe directly transmits signals to the first radiation patch and transmits the signals to the second radiation patch through electromagnetic coupling.

[0014] Furthermore, stub lines are provided on both the first radiation patch and the second radiation patch, and the stub lines are provided at the centers of the four sides of the corresponding radiation patch.

[0015] The beneficial effects of the present invention include: 1. Miniaturized design of the dual-band and dual-polarization transceiver integrated antenna. When two antennas with relatively close operating frequency bands are directly placed together, they are prone to interference with each other. For example, the existing BDS L-band and BDS B1 frequency point transceiver antennas only differ by 20 MHz. To shield interference, generally, the two-band antennas are arranged in parallel or other antennas with relatively far operating frequency bands are used for spacing. Although the interference is shielded, the antenna size is large and not suitable for miniaturized platforms. Therefore, in the present invention, the two antennas are directly stacked, and considering that the two antenna frequency bands are relatively close, a coupled feeding method can be used to realize the feeding between the antennas, thereby reducing the number of feeding ports and the complexity of the feeding network. In the stacked design, a large amount of space can be saved. At the same time, based on the stripline coupler, multiple-section branch lines are added, and the parasitic effect is offset by multi-path coupling to improve the port isolation degree, so as to realize the miniaturized design of the antenna without affecting the antenna performance.

[0016] 2. Miniaturized high-isolation feeding network design. In order to realize left-handed circular polarization and right-handed circular polarization, the existing BDS L-band and BDS B1 frequency point feeding networks adopt independent feeding networks, which is not conducive to high-integration design and will increase the antenna structure size. The present invention is designed based on the stripline coupler, and multiple-section branch lines are added to realize frequency band expansion and isolation improvement. Through the design of the operating frequency band of the stripline coupler, the design method of the present invention can be applied to the miniaturized design of dual-band and dual-polarization antennas in other frequency bands.

[0017] 3. Antenna feeding method. The two-band antennas share a feeding port, and the upper and lower radiation patches are fed in a common feeding manner. The feeding probe passes through the via hole of the lower patch antenna and is connected to the upper patch antenna. The upper patch antenna is directly fed through the feeding probe, and the lower patch antenna is fed by coupling through the feeding probe. This method reduces the number of feeding ports and the complexity of the feeding network, can greatly save space in the stacked design, and is beneficial to the miniaturization of the product. Especially in multi-band applications, two-band sharing or three-band sharing can be achieved. The design method of the present invention can also adopt common feeding technologies such as single feeding point or multi-feeding points to achieve the purpose.

[0018] 4. Feeding circuit for two antennas sharing. According to the performance of the four ports of the coupler, one coupler is used to excite two antennas to form two circularly polarized waves with different polarizations. Compared with the conventional dual circularly polarized antenna that requires two couplers to achieve different polarization modes, the feeding circuit of the present invention saves the space of the dielectric substrate, is suitable for miniaturization scenarios, simplifies the processing complexity at the same time, and reduces the manufacturing cost. Brief Description of the Drawings

[0019] Figure 1 It is a two-dimensional structural schematic diagram of a dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna according to an embodiment of the present application.

[0020] Figure 2 It is a three-dimensional structural schematic diagram of a dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna according to an embodiment of the present application.

[0021] Figure 3 It is a structural schematic diagram of a three-branch stripline coupler according to an embodiment of the present application.

[0022] Figure 4 It is a schematic diagram of a coaxial dual-point probe according to an embodiment of the present application.

[0023] Figure 5 It is a gain schematic diagram of a dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna working in the L band according to an embodiment of the present application.

[0024] Figure 6 It is an axial ratio schematic diagram of a dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna working in the L band according to an embodiment of the present application.

[0025] Figure 7 It is a gain schematic diagram of a dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna working in the B1 band according to an embodiment of the present application.

[0026] Figure 8 It is an axial ratio schematic diagram of a dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna working in the B1 band according to an embodiment of the present application.

[0027] Figure 9 This is a schematic diagram of the isolation between two ports when a dual - frequency, high - isolation, compact Beidou - III satellite transceiver integrated antenna involved in the embodiment of the present application operates in the transmitting frequency band. Accompanying drawing

[0028] 1 - First radiation patch, 2 - First dielectric substrate, 3 - First metal floor, 4 - Second radiation patch, 5 - Second dielectric substrate, 6 - Second metal floor, 71 - SMA RF connector of antenna L, 72 - SMA RF connector of antenna B1, 8 - Feeding circuit board, 9 - Three - branch strip - line coupler, 10 - Metal feeding pin, 11 - Screw, 91 - First port, 92 - Second port, 93 - Third port, 94 - Fourth port, 95 - Main coupling line, 96 - Sub - coupling line, 97 - First branch line, 98 - Second branch line, 99 - Third branch line. Detailed implementation manners

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Therefore, the detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0030] The following combines the accompanying Figure 1-2 to make a detailed description of the specific embodiments of the present invention; A dual - frequency, high - isolation, compact Beidou - III satellite transceiver integrated antenna mainly includes two parts of technologies. One is the miniaturization design of the transceiver integrated antenna, and the other is the high - isolation design for receiving and transmitting signals between adjacent frequency bands. Specifically, in this embodiment, the adjacent frequency bands refer to the L - band and the B1 - band.

[0031] In terms of the high isolation design for reception and transmission: The high isolation performance for reception and transmission is achieved through the feed circuit board. The existing 3dB stripline coupler has problems of low relative bandwidth and low isolation between ports. In the present invention, a coupler branch line is introduced and the branch line is extended to three sections. The bandwidth is broadened through a cascaded structure, and at the same time, the parasitic effect is eliminated by multi-path coupling to improve the port isolation. This coupler has the effect of broadband and high isolation. Signals with the same amplitude and a phase difference of 90° are provided to two metal feed pins through the output end. The input end and the isolation end of the coupler are respectively connected to the SMA RF connectors of antenna B1 and antenna L, thereby forming left-handed circular polarization radiation and right-handed circular polarization radiation, ensuring that the receiving and transmitting antennas have different polarization modes and good isolation. Specifically, a dual-frequency high isolation compact Beidou-3 satellite transceiver integrated antenna uses a microstrip patch antenna stack to achieve dual-frequency design and introduces a 3dB coupler to realize a high isolation transceiver antenna with dual circular polarization. It includes: a first antenna, a second antenna, and a feed circuit board 8 stacked in sequence from top to bottom.

[0032] Specifically, the feed circuit board 8 includes a three-branch stripline coupler 9, as Figure 3 shown. The three-branch stripline coupler 9 includes a main coupling line 95 and a secondary coupling line 96 symmetrically arranged. A first branch line 97, a second branch line 98, and a third branch line 99 are connected between the main coupling line 95 and the secondary coupling line 96. The left and right ends of the main coupling line 95 are respectively a first port 91 and a third port 93, and the left and right ends of the secondary coupling line 96 are respectively a second port 92 and a fourth port 94.

[0033] The distance between the first branch line 97 and the second branch line 98 is equal to the distance between the second branch line 98 and the third branch line 99.

[0034] When any one of the first port 91, the second port 92, the third port 93, and the fourth port 94 is used as the input port, the corresponding port symmetric to it on the other coupling line serves as the isolation port due to the mutual cancellation of electromagnetic waves, and the remaining two ports are the output ports.

[0035] The two output ports respectively output signals with equal amplitude and a phase difference of 90°, and when transmitted to the first antenna and the second antenna, left-handed circular polarization waves or right-handed circular polarization waves can be formed.

[0036] For example, when the first port 91 serves as the input end, the first port 91 is the input port of the coupler, the second port 92 is the isolation port of the coupler, the third port 93 is the through port of the coupler, and the fourth port 94 is the coupled port of the coupler. Specifically, the lengths of the main coupling line 95 and the secondary coupling line 96 are 1 / 2 wavelength, and the lengths of the first branch line 97, the second branch line 98, and the third branch line 99 are 1 / 4 wavelength. For the electromagnetic waves reaching the third port 93 and the fourth port 94, the amplitudes of these two signals are the same, and the phase deviation is 90 degrees due to the path difference. There are two paths for the electromagnetic wave reaching the second port 92. The amplitudes of these two signals are the same, but the phase difference caused by the path difference is 180 degrees. After convergence, the electromagnetic waves exactly cancel each other out. Therefore, no signal passes through the second port 92, which serves as the isolation port.

[0037] The three-branch stripline coupler 9 has a high degree of symmetry, and any port can be used as the input end.

[0038] In another embodiment, in terms of miniaturization design: In order to enable the antenna to operate at different resonant frequencies in the L band and the B1 band, and to achieve left-handed circular polarization and right-handed circular polarization respectively, a double-layer microstrip antenna is used to realize the dual-band and dual-polarization function. The transceiver antenna includes a first antenna, a second antenna, and a feeding circuit board 8, which are stacked in sequence from top to bottom. The first antenna includes a first dielectric substrate 2, a first radiation patch 1 disposed on the upper surface of the first dielectric substrate 2, and a first metal floor 3 disposed on the lower surface of the first dielectric substrate 2, and operates in the L band; the second antenna includes a second dielectric substrate 5, a second radiation patch 4 disposed on the upper surface of the second dielectric substrate 5, and a second metal floor 6 disposed on the lower surface of the second dielectric substrate 5, and operates in the B1 band. The first radiation patch 1 and the second radiation patch 4 are fed in a common feeding manner. The feeding probe passes through the via hole of the second antenna and is connected to the first antenna. The first antenna is directly fed through the feeding probe, and the second antenna is coupled and fed through the feeding probe. Using a coaxial probe for feeding is beneficial to realizing the miniaturization of the radiation patch size; the upper and lower patches adopt a tightly coupled feeding method to realize the multi-band feeding of the multi-layer radiation patches, achieving the miniaturization effect of the overall antenna.

[0039] The feeding circuit board 8 directly feeds the first antenna, and the second antenna is coupled and fed through the feeding probe.

[0040] The first dielectric substrate 2, the first radiation patch 1 disposed on its upper surface, and the first metal floor 3 disposed on its lower surface form an L antenna. The second dielectric substrate 5, the second radiation patch 4 disposed on its upper surface, and the second metal floor 6 disposed on its lower surface form a B1 antenna. Both the first dielectric substrate 2 and the second dielectric substrate 5 are square structures.

[0041] The feeding circuit board 8 includes a feeding probe. The feeding probe sequentially passes through the second metal floor 6, the second dielectric substrate 5, the second radiation patch 4, the first metal floor 3, and the first dielectric substrate 2 through vias, and is connected to the upper surface of the first radiation patch 1. The size of the via is larger than the outer diameter of the feeding probe, so that the second radiation patch 4, the second dielectric substrate 5, the second metal floor 6, the first dielectric substrate 2, and the first metal floor 3 do not contact the feeding probe. The feeding probe directly transmits the signal to the first radiation patch 1 and transmits the signal to the second radiation patch 4 through electromagnetic coupling.

[0042] There are metallized vias with a diameter of 2 mm at the centers of the first dielectric substrate 2, the second dielectric substrate 5, and the feeding circuit board 8, forming a short-circuit antenna for lightning protection design to protect the backend circuit, and the diameter size of the vias can be changed. The antenna is fixed by a screw 11 passing through the central vias of the first radiation patch 1, the first dielectric substrate 2, the first metal floor 3, the second radiation patch 4, the second dielectric substrate 5, the second metal floor 6, and the feeding circuit board 8 and fixed to the back of the feeding circuit board 8.

[0043] In another embodiment, the feeding probe is a coaxial double-point probe, as Figure 4 shown, including two metal feeding pins 10. The angle formed by the two metal feeding pins 10 connected to the central axis of the dielectric substrate of the feeding circuit board 8 is 90°. The second radiation patch 4, the second dielectric substrate 5, the second metal floor 6, the first dielectric substrate 2, and the first metal floor 3 are correspondingly opened at the positions where the metal feeding pins 10 pass through to avoid contacting the metal feeding pins 10.

[0044] In another embodiment, the first antenna is used as an L antenna, and the second antenna is used as a B1 antenna. Since the B1 antenna needs to form a right-handed circularly polarized wave and the L antenna needs to form a left-handed circularly polarized wave, the specific port definitions are as follows: The first port 91 is externally connected to the SMA RF connector 71 of the antenna L, the second port 92 is externally connected to the SMA RF connector 72 of the antenna B1, the third port 93 and the fourth port 94 are respectively connected to the lower ends of the two metal feeding pins 10, and the upper ends of the metal feeding pins 10 are connected to the upper surface of the first radiation patch 1. By designing a 3 dB coupler with high isolation, the isolation between the transceiver ports can be effectively improved, and a left-handed circularly polarized wave and a right-handed circularly polarized wave are respectively provided, realizing a dual-band dual-circularly polarized high-isolation transceiver antenna.

[0045] The size of the first dielectric substrate 2 is 29 mm × 29 mm × 5 mm, and the size of the second dielectric substrate 5 is 43 mm × 43 mm × 9 mm. A relatively thick dielectric substrate is used to improve the antenna gain.

[0046] The dielectric constant of the first dielectric substrate 2 is 16, and the dielectric constant of the second dielectric substrate 5 is 8. High-dielectric-constant plates are used to reduce the antenna size and achieve miniaturized design. Dielectric plates with different dielectric constants are used to make the radiation patch of the lower-layer antenna larger than that of the upper-layer antenna dielectric substrate, so as not to block the radiation patch of the lower-layer antenna and enable it to form effective radiation.

[0047] The lengths of the main coupling line 95 and the secondary coupling line 96 are 1 / 2 wavelength. The lengths of the first branch line 97, the second branch line 98, and the third branch line 99 are 1 / 4 wavelength. The second branch line 98 is disposed between the first branch line 97 and the third branch line 99. The impedances of the main coupling line 95, the secondary coupling line 96, and the second branch line 98 are 36.38 Ω, and the impedances of the first branch line 97 and the third branch line 99 are 129.96 Ω.

[0048] Both the first radiation patch 1 and the second radiation patch 4 are provided with stub lines. The stub lines are disposed at the centers of the four sides of the corresponding radiation patch. Specifically, the first radiation patch 1 has a square structure with a side length of 20.7 mm. The length and width of the stub line disposed on the first radiation patch 1 are 5 mm and 1.5 mm respectively. The second radiation patch 4 also has a square structure with a side length of 30.4 mm. The length and width of the stub line disposed on the second radiation patch 4 are 6 mm and 3 mm respectively, which are used for fine-tuning the resonant frequency. The cut-off angle is 2 mm to change the current path and improve the circular polarization performance. At the same time, a circular polarization performance adjustment point can be reserved here.

[0049] The four corners of the first radiation patch 1 and the second radiation patch 4 are subjected to a 1-mm cut-off treatment.

[0050] Figure 2 The cylinder on the feeding circuit board 8 described above is a metallized via hole, which is for electromagnetic shielding. At the same time, the vias on the four sides are for the upper and lower planes to be grounded together (in the figure, a transparent treatment is made to show all the structures).

[0051] The antenna designed in this embodiment is subjected to simulation analysis, and the results are as Figures 5-8 shown.

[0052] Figure 5 This is the gain pattern of the antenna at the center frequency of the L band. It can be seen from the figure that the normal gain is 6.56 dBi, and the gain at an elevation angle of 20° is -0.42 dBi, having good radiation gain and low-elevation-angle performance.

[0053] Figure 6 This is the axial ratio pattern of the antenna at the center frequency of the L band. It can be seen from the figure that the normal axial ratio of the L-band antenna is 0.31 dB, having a good circular polarization effect.

[0054] Figure 7It is the gain pattern of the antenna at the center of the B1 band. As can be seen from the figure, the normal gain is 5.49 dBi, and the gain at an elevation angle of 20° is -1.20 dBi, having good radiation gain and low elevation angle performance.

[0055] Figure 8 It is the axial ratio pattern of the antenna at the center frequency of the B1 band. As can be seen from the figure, the normal axial ratio of the B1 band antenna is 0.43 dB, having a very good circular polarization effect.

[0056] Figure 9 It is the isolation between two ports when the antenna is operating in the transmit band. As can be seen from the figure, the maximum isolation between two ports in the transmit band reaches 43.7 dB.

[0057] The above-described embodiments merely represent the specific implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application.

Claims

1. A dual-frequency high-isolation compact integrated receiving and transmitting antenna for Beidou-3 satellites, characterized in that, Comprising: A first antenna, a second antenna, and a feeding circuit board stacked in sequence from top to bottom. The feeding circuit board includes a three-branch strip-line coupler. The three-branch strip-line coupler includes a main coupling line and a sub-coupling line symmetrically arranged. A first branch line, a second branch line, and a third branch line are connected between the main coupling line and the sub-coupling line. The left and right ends of the main coupling line are a first port and a third port respectively, and the left and right ends of the sub-coupling line are a second port and a fourth port respectively.

2. The dual-frequency high-isolation compact Beidou-3 satellite transceiver integrated antenna according to claim 1, wherein The main coupling line and the sub-coupling line have the same length. The first branch line, the second branch line, and the third branch line have the same length. The length of the main coupling line is twice the length of the first branch line.

3. The dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna according to claim 2, wherein When any one of the first port, the second port, the third port, and the fourth port is used as an input port, the corresponding port symmetric to it on the other coupling line serves as an isolation port due to the cancellation of electromagnetic waves, and the remaining two ports are output ports.

4. A triple-band high-isolation compact Beidou-3 satellite transceiver integrated antenna according to claim 3, wherein The two output ports respectively output signals with equal amplitudes and a phase difference of 90°. When transmitted to the first antenna and the second antenna, a left-handed circularly polarized wave or a right-handed circularly polarized wave can be formed.

5. The dual-frequency high-isolation compact BeiDou-3 satellite transceiver integrated antenna according to claim 2, wherein The lengths of the main coupling line and the sub-coupling line are half a wavelength. The lengths of the first branch line, the second branch line, and the third branch line are a quarter of a wavelength. The second branch line of the main coupling line and the sub-coupling line is disposed between the first branch line and the third branch line. The main coupling line, the sub-coupling line, and the second branch line have the same impedance. The first branch line and the third branch line have the same impedance, and the impedance of the main coupling line is less than the impedance of the first branch line.

6. The dual-band high-isolation compact Beidou-3 satellite transceiver integrated antenna according to claim 1, wherein The feeding circuit board directly feeds the first antenna through a feeding probe, and the second antenna is fed by coupling through a feeding probe.

7. A triple-band high-isolation compact integrated receiving and transmitting antenna for Beidou-3 satellites according to claim 6, wherein The first antenna includes a first dielectric substrate, a first radiation patch disposed on the upper surface of the first dielectric substrate, and a first metal ground disposed on the lower surface of the first dielectric substrate. The second antenna includes a second dielectric substrate, a second radiation patch disposed on the upper surface of the second dielectric substrate, and a second metal ground disposed on the lower surface of the second dielectric substrate.

8. A triple-mode high-isolation compact Beidou-3 satellite transceiver integrated antenna according to claim 7, wherein The feeding circuit board includes a feeding probe. The feeding probe sequentially passes through the second metal ground, the second dielectric substrate, the second radiation patch, the first metal ground, and the first dielectric substrate and is connected to the first radiation patch. The second radiation patch, the second dielectric substrate, the second metal ground, the first dielectric substrate, and the first metal ground are not in contact with the feeding probe. The feeding probe directly transmits the signal to the first radiation patch and transmits the signal to the second radiation patch through electromagnetic coupling.

9. A dual-frequency high-isolation compact Beidou-3 satellite transceiver integrated antenna according to claim 7, characterized in that, Both the first radiation patch and the second radiation patch are provided with stubs, and the stubs are disposed at the centers of the four sides of the corresponding radiation patch.

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